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Logicial block protection for tape interchange

a logic block and tape technology, applied in the field of data storage using lbp, can solve the problem of too much information written to tap

Inactive Publication Date: 2014-09-18
HEWLETT-PACKARD ENTERPRISE DEV LP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention describes a method for ensuring accurate records are written and retrieved from tape devices. The method involves appending a cyclic redundancy check (CRC) to the end of a record, followed by a string of zeros. The record is then sent to tape devices that support logical block protection (LBP). LBP devices will not remove any digits from the record, while non-LBP devices will add a string of zeros and strip it on read back. This ensures that too much or too little information is written to the tape, depending on the device's capabilities. The invention allows for seamless compatibility with different types of tape drives.

Problems solved by technology

Thus, there would be too much information written to tape if the zeros were left in the record.

Method used

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  • Logicial block protection for tape interchange
  • Logicial block protection for tape interchange
  • Logicial block protection for tape interchange

Examples

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Embodiment Construction

[0014]A two part process is used for modifying records to be written and retrieved from tape devices to ensure the records are accurate when received and written to different tape devices having different error checking methods. A record is first accessed and a cyclic redundancy check is appended to the end of the record. After appending the CRC, a string of zeros is appended to the end of the CRC as part of the record. The record, with an additional CRC and the string of zeros, may then be submitted to tape drives which are logical block protection enabled. Drives which are logical block protection (LBP) enabled will not remove any of the digits from the record.

[0015]For drives that are not LBP enabled, the string of zeros at the end of the record is removed prior to sending the record, and restored after receiving the data on read back. This is done because non-LBP enabled drives will add a string of zeros themselves. Thus, there would be too much information appended to the drive...

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Abstract

A two part process is used for modifying records to be written and retrieved from tape devices. A record is appended with a cyclic redundancy check and a string of zeros. Submitting the entire record to tape drives which are logical block protection enabled will result in no change. For drives that are not LBP enabled, the string of zeros at the end of the record is removed. In addition to determining whether a drive is LBP compliant, a determination may be made as to whether a drive is a linear tape open drive from a particular manufacturer. Linear tape open drives may behave similarly as drives which may not be enabled with logical block protection.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates data storage using LBP. In particular, the present invention relates to implementing CRC data storage techniques across many different devices.[0003]2. Description of the Related Art[0004]Detecting errors in data as a result of transmission, data operators, and other functions has been done with logical block detection (LBP), the technique of adding a 32-bit cyclic redundancy check (CRC) checksum to tape records, is an old technique. IBM Corporation has used this method invisibly on their a linear-tape-open (LTO) drives for years to ensure data integrity, adding the CRC to the data record before writing it to tape, then checking and stripping the CRC before returning it to the application on readback.[0005]IBM has more recently publicized this method through a change to the T10 SCSI specification, which allows the tape drive to make the CRC visible to the application. The application now ad...

Claims

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Application Information

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IPC IPC(8): G11B20/12
CPCG11B20/1202G11B2020/1843G11B20/1833G11B5/00813G06F3/0619G06F3/064G06F3/0682G06F11/1004
Inventor REHM, KEVAN FLINTSCHMITZ, JUDITH ANNNEMETH, JOSEPH CARLSYGULLA, JOHN MICHAEL
Owner HEWLETT-PACKARD ENTERPRISE DEV LP